Preheat oven to 350°F. Cook and stir meat and onions in large skillet on medium heat until meat is browned and onions are tender; drain. Return meat mixture to skillet. Add 1/2 cup of the enchilada sauce; mix well.

Spread 1/2 cup of the remaining enchilada sauce onto bottom of 13×9-inch baking dish. Spoon 1/4 cup of the meat mixture down center of each tortilla; roll up. Place, seam-sides down, in baking dish; top with the remaining 1 cup enchilada sauce and the Velveeta.

Bake 20 min. or until enchiladas are heated through and Velvetta is melted.